The Reference scenario and the Energy [R]evolution scenario are based on the same projections of population and economic development.
The future development of energy intensity, however, differs between the reference and the alternative case, taking into account the measures to increase energy efficiency under the Energy [R]evolution scenario.

global: heating supply

Renewables currently provide 25% of the global energy demand for heat supply, the main contribution coming from the use of biomass. In the Energy [R]evolution scenario, renewables provide 51% of global total heat demand in 2030 and 91% in 2050. The lack of district heating networks is a severe structural barrier to the large scale utilisation of geothermal and solar thermal energy as well as the lack of specific renewable heating policy. Past experience shows that it is easier to implement effective support instruments in the grid-connected electricity sector than in the heat market, with its multitude of different actors. Dedicated support instruments are required to ensure a dynamic development.

Energy efficiency measures can decrease the demand for heat supply by 23 % compared to the Reference scenario, in spite of a growing global population, increasing economic activities and improving living standards.

For direct heating, solar collectors, biomass/biogas as well as geothermal energy are increasingly substituting for fossil fuelfired systems.

The introduction of strict efficiency measures e.g. via strict building standards and ambitious support programs for renewable heating systems are needed to achieve economies of scale within the next 5 to 10 years.

Table 5.3 shows the worldwide development of the different renewable technologies for heating over time. Up to 2020 biomass will remain the main contributor of the growing market share. After 2020, the continuing growth of solar collectors and a growing share of geothermal energy and heat pumps will reduce the dependence on fossil fuels.